Numerous prior art patents have been issued on apparatus for collecting, storing and transferring solar heat energy. Such apparatus and/or systems typically employ two liquid systems, a hot water utilization system including a potable hot water storage tank having a cold water inlet and hot water outlet and a re-circulating solar heating fluid system including a solar collection panel, a gravity drain tank and a heat exchange coil. In one common form of such apparatus the solar energy is incident on and absorbed by a metallic plate or “black body”, which effectively converts it to a black body type of radiator. The black body surface is encased within a transparent ceramic or plastic material that permits the transfer of light there through, but reflects back toward the heat absorbing black plate substantially all infrared radiation emitted by the black body plate. The heat developed in the black body is then transferred to a fluid which passes through copper tubes lined in an adjacent relationship to the black body heat absorbing plate.
One example of, a solar thermal water heating system is disclosed in Fossum et al U.S. Pat. No. 5,575,276. As disclosed therein, a solar thermal water heating system includes a solar collector unit, first and second heat exchangers, and a drain back tank, ordered respectively in vertically descending relation. The solar energy collector comprises a plurality of heat absorbing modules formed by deforming two plates into intimate contact with parallel metallic pipes disposed intermediate the plates. The uppermost surface of the pair of plates is provided with a black body coating to emit infrared radiation when sunlight is incident thereon. A glazing is provided over such black body surface to freely transmit incident light to the black body surface but to reflect infrared heat energy emitted by the black body surface. A pump for pumping fluid from the drain back tank to the solar collector unit is positioned horizontally adjacent the drain back tank. The first heat exchanger is vertically disposed within the water storage tank for conducting heat to potable water within the storage tank. When the system shuts down, the thermally conductive fluid drains into the first heat exchanger and drain back tank providing freeze protection for the solar collector unit.
The use of black top driveways, parking lots and the like in thermal heating systems are also well known. For example, Brugger U.S. Pat. No. 4,037,652 discloses a solar heat storage system and a solar heat collection mechanism wherein a plurality of conduits lying below street level are covered by a layer of blacktop. The collection mechanism includes a network of serially connected conductive conduits arranged in a serpentine fashion and coupled to a source of antifreeze.
An additional approach to the utilization of fluid containing conduits embedded in a roadway is disclosed in Wendel U.S. Pat. No. 4,132,074. As disclosed, the fluid circulated through the conduit is heated by the paving and cools the paving to prolong the useful life and can be used to reduce heat transmission through the roofing to the interior of a building. One example, refers to a heated swimming pool heated by a collector forming a part of a parking lot or generating electric power by use of a collector from a part of a highway.
A solar energy collection system is disclosed in Tinari U.S. Pat. No. 6,446,625. Tinari discloses a system that can be retro fitted into pavement covered lots with a pump and heat exchanger connected to and a conduit buried below the paved surface. The conduit has a hollow unitary, one-piece casting with an oval cross-section and an internal divider that divides the interior of a casing into two passageways. Heat conducted fins are mounted on the casing.
It has now been recognized that in some countries, summer temperatures may reach or exceed 50° C. (122° F.) in the shade and in those countries, it should be possible to utilize existing roads or newly constructed roads as heat engines due to their black body surface that can convert solar energy into thermal energy. For example, the high temperature during the day can be used to boil seawater pumped thorough a piping network and directing the pressurized steam into turbines to generate electric energy. Then as the steam cools down, the condensed water can be used as brackish water suitable for agriculture or can undergo further desalination to produce drinking water that is suitable for human consumption.
Thus, the ultimate aim of the present invention is to use an abundance of solar energy as an efficient, environmental friendly and cost effective energy alternative for water desalination and generation of electricity.